Milk to foreign markets new demands to shelf life and improved quality

Valentin Rauh - Mejeriforskningsdagen 2017

Topics

07 March 2017 2

Enzymes in UHT milk

Lactose hydrolysed milk

Transport and storage conditions

Future needs

Lactose hydrolysed milk

07 March 2017 3

Lactose hydrolysed milk

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Effect of side activity in posthydrolysed milk

Proteolytic side activity of lactase preparations

Release of amino acids

Enhanced formation of Maillard off flavours and bitter

peptides

[Jansson, 2014]

Lactose hydrolysed milk

• Collaboration with Aarhus University • Quick test for proteolytic side activity

• Testing of commercial lactase preparations

• Large difference in proteolytic activity • All preparations showed side activity

• Rapid evaluation of new lactases and their risk for off flavour generation

• Ability to choose right lactase for right application

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Side activity testing

Lactose hydrolysed milk

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Off flavour development

Storage time

Off f

lavo

ur

7 months 12 months

Lactose hydrolysed milk

• Pelum: Polyphenol Enriched Lactosefree UHT Milk

• Plant polyphenols can inhibit Maillard reaction

• Aim: • Understanding the interactions between polyphenols and

milk components for a possible reduction in off-flavor formation

• Storage trial to evaluate effect of polyphenols in lactose free UHT milk

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Inhibiting Maillard reactions

Enzymes in UHT milk

07 March 2017 8

Enzymes in UHT milk

07 March 2017 9

Bacterial enzymes - contamination

Farm/ Milking Raw milk in dairy Pasteurized milk in dairy

UHT Raw milk storage and transport

• Problem in final product • If contamination of milk by bacteria • If bacteria can grow under cold storage conditions • If bacteria secret enzymes • If the enzymes are heat resistant • If shelf life is long enough for residual enzymes to do damage

BUT if it happens, the whole production is spoiled

Enzymes in UHT milk

• New quality recommendations for dairies

• Analysis setup to check proteolysis

• Changing perception of UHT

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Outcome

Enzymes in UHT milk

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PhD project Lund University

To increase the profitability of milk production, it is required that milk and dairy products can be stored for a long time. The shelf-life of milk is controlled by quality parameters, such as enzymatic changes in the milk. These impair the shelf-life by giving rise to taste, odor and product defects, which in turn gives a higher waste.

Milk quality and increased shelf-life of milk

07 March 2017 12

Transport and storage

Transport and storage

07 March 2017 13

Accelerated shelf life test of UHT milk

[Sunds, 2016]

Transport and storage

07 March 2017 14

Browning of UHT milk

[Sunds, 2016]

Transport and storage

• No significant changes at 10 and 20 °C, some changes after storage at 30 °C

• Major changes at 40 and 50 °C • Colour changes • Maillard reaction products • Lipid oxidation products • New reactions compared to 20 °C, e.g. sugar degradation

• Faster reactions during temperature cycling compared to average temperature

• Colour analysis was an easy and robust method for Maillard reaction

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Key outcomes

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Accelerated or ambient storage?

Transport and storage

• New initiatives regarding transportation and distribution

• Rethinking storage and shelf life tests

• Exploring optimal balance between storage temperature and shelf life

• New approaches for accelerated shelf life tests needed

07 March 2017 17

Started activities

Storage temperature

Shel

f life

Future research needs

• Analysis of contamination by psychrotrophs • Bacteria vs enzymes vs DNA/ RNA • Analysis prior to production

• Extended cold storage

• Microbial spoilage • Impact on structure and functionality

• Accelerated shelf life testing

• Validated protocol • Methods and knowledge for functionality of different products

07 March 2017 18

Future research needs

• Powder functionality • Solubility • Wettability • Crystallization • Enzyme activity • Formulation for specific products

• Powder shelf life • Impact on functionality • Off flavour generation

07 March 2017 19

Recombination